This is what I get:
$ repoman --version
Usage: repoman [options] [mode]
repoman: error: no such option: --version
--version is listed in the man page though and should in my eyes be supported.
Steps to Reproduce:
portage 2.2 is also affected by this bug
Thanks, this is fixed in svn r12293.
This is released in 220.127.116.11 and 2.2_rc19.